The invention relates to a device for translating a slide, which device comprises a frame and mutually parallel first and second guide rods. First and second bearing means cooperate with respective guide rods to guide the slide relative to the frame in a rectilinear path along a first axis of an orthogonal triaxial system.
Netherlands Patent Application 8204981 (PHN 10.530, herewith incorporated by reference) discloses a device employed in an electrodynamic apparatus for translating an objective along a radial path relative to a disc which rotates about an axis of rotation. The object is arranged on a slide which can be translated relative to the frame along the radial path. The two parallel guide rods are of circular cross-section and are secured to the frame; four conventional bearing sleeves which are secured to the frame cooperate pairwise with the guide rods. The bearing sleeves comprise cylindrical bearing members which fit coaxially around the guide rods in such a way that a specific clearance exists between the guide rods and the bearing members. The slide is driven by two permanent-magnetic stator magnets parallel to the path and secured to the frame and two drive coils connected to the slide and which can be translated in the magnetic field produced by the stator magnets.
A drawback of the known device is that the rectilinear guide means for the slide is susceptible to alignment errors of the guide rods; even a slight deviation in the parallel arrangement of the guide rods gives rise to additional friction in the bearing means, which is liable to give rise to stick-slip effects and which may even cause jamming of the slide. Therefore, it is necessary to accurately machine mounting faces on the frame in order to ensure an exact positioning of the guide rods. An additional disadvantage is that the intricate mounting of the guide rods results in a higher cost of the rectilinear guide means and hence a higher cost of the device. These disadvantages become even more serious in view of the general trend towards and the consequent progress in miniaturization.